Silvercorp completed 72,878 m of underground drilling in 704 diamond drill holes at the GC mine from October 1, 2019 to June 30, 2021. The program targeted: 1) known silver-lead-zinc veins in and above the production area that were previously missed due to limited exploration, changes in the strikes/dips, and/or pinch-swelling of the pay-zones, and 2) the north and south sides of the resource area at higher elevations.
High-grade intercepts of known silver-lead-zinc veins within the production area:
- Hole 20CK24A02 intersected a 6.13 m interval (6.01 m true width) of vein V2E1 grading 258 g/t silver, 7.05% lead, and 7.05% zinc from 53.41 m depth, at an elevation of -211 m, including a 1.10 m interval (1.08 m true width) grading 462 g/t silver, 25.57% lead, and 5.21% zinc.
- Hole 20CK3025 intersected a 2.93 m interval (2.79 m true width) of vein NV28 grading 417 g/t silver, 19.22% lead, and 1.72% zinc from 38.96 m depth, at an elevation of -11 m, including a 1.48 m interval (1.34 m true width) grading 815 g/t silver, 37.47% lead, and 2.12% zinc.
High-grade intercepts of newly discovered silver-lead-zinc veins within the production area:
- Hole 20CK11805 intersected a 0.74 m interval (0.74 m true width) of vein V18-3 grading 557 g/t silver, 1.21% lead, and 14.82% zinc from 104.30 m depth, at an elevation of -11 m.
- Hole 20CK11808 intersected a 0.56 m interval (0.38 m true width) of vein V18-4 grading 533 g/t silver, 2.98% lead, and 7.51% zinc from 104.05 m depth, at an elevation of 24 m.
High-grade intercepts of newly discovered silver-lead-zinc veins south of the resource area:
- Hole 20CK46A01 intersected a 0.87 m interval (0.46 m true width) of vein V33-2 grading 994 g/t silver, 5.18% lead, and 5.52% zinc from 57.56 m depth, at an elevation of 149 m. The hole also intersected a 0.74 m interval (0.56 m true width) of vein V33-1 grading 447 g/t silver, 2.04% lead, and 5.28% zinc from 72.76 m depth, at an elevation of 146 m
- Hole 21CK4820 intersected a 2.16 m interval (1.30 m true width) of vein V35 grading 539 g/t silver, 8.06% lead, and 3.23% zinc from 47.55 m depth, at an elevation of 140 m.
High-grade intercepts of newly discovered silver-lead-zinc veins north of the resource area:
- Hole 20CK4802 intersected a 0.47 m interval (0.46 m true width) of vein NV6 grading 115 g/t silver, 0.54% lead, and 18.05% zinc from 135.29 m depth, at an elevation of 39 m.
Data from the 2020-2021 exploration program underpinned an updated mineral resources and reserves estimate in August 2021 (effective December 31, 2020). Compared to the previous estimate (effective June 30, 2019):
- Combined Proven and Probable tonnes increased by 8%.
- Measured tonnes increased by 57% due to new discoveries, new vein interpretations, and conversion of Indicated tonnes (decreased by 17%).
- Inferred tonnes increased by 17%.
In fiscal year 2023, Silvercorp plans to complete 61,400 m of exploration drilling (capitalized and expensed) at GC. The current drill program is complemented by 20,800 m of exploration and development tunnels (capitalized and expensed).
The Mineral Resource estimates for the Gaocheng property were prepared by Mr. Shoupu Xiang, Resource Geologist of Silvercorp, and were reviewed by independent Qualified Person, Ms. Dinara Nussipakynova, P.Geo of AMC who takes responsibility for the estimates. The data used in the Mineral Resource estimation includes results of all drilling carried out on the Property to 31 December 2020. The estimation was carried out in Micromine™ software. Interpolation was carried out using inverse distance squared (ID2) for all the veins.
The Mineral Resources are reported above a cut-off of 105 g/t silver equivalent (AgEq). Cut-off grades are based on in situ values in AgEq terms in grams per tonne (after application of mining recovery and payable values) and incorporate all mining and processing costs provided by Silvercorp and reviewed by AMC.
The estimated Mineral Resources and metal content for the property as of December 31, 2021 are detailed in Table 1 below.